This invention relates generally to gas insulated equipment, and more particularly to a gas insulated transmission line.
A typical gas insulated transmission line comprises a cylindrical, elongated outer sheath, a cylindrical, elongated inner conductor disposed within the outer sheath, and an insulating gas to electrically insulate the high potential inner conductor from the low potential, or grounded, outer sheath. Spaced along the inner conductor are insulators for supporting the inner conductor concentrically within the outer sheath. These insulators are typically spaced at 20 foot intervals, and are generally of a silica-filled epoxy because of its desirable electrical and mechanical properties. The spacers usually are cast either directly onto the conductor, or onto a conductor sleeve which is then welded to the inner conductor. A drawback to the use of such silica-filled epoxy spacers, however, is that they are quite expensive. The material costs for the spacer assembly for a 230 kilovolt sulfur hexafluoride insulated transmission line may approach 16% of the total material cost of the line. It can thus be seen that it is desirable to reduce the cost of the spacer assembly, particularly if new designs of such gas insulated transmission lines mandate an increased number of spacers.